Summit analysis: If the talks collapse, it will probably be over how power is distributed in a Union of 25 member-states, writes Denis Staunton, in Brussels.
This weekend's meeting of EU leaders in Brussels is the most thoroughly prepared summit in European history, following almost two years of negotiations towards a constitutional treaty.
Despite the work of the Convention on the Future of Europe and the efforts of hundreds of diplomats, however, many predict that the talks will end in failure tomorrow night.
The 15 member-states and the 10 countries that will join the EU next year agree on almost everything in the draft treaty, which will replace all previous EU treaties and give the Union a single legal personality.
If the talks collapse, it will probably be over a bitter disagreement on the fundamental question of how power is distributed in a Union of 25 member-states.
Unlike at Nice in 2000, the 10 new member-states have full negotiating rights at this weekend's summit and they have made clear that they are determined that their voice will be heard.
Poland, the largest, has made common cause with Spain to defend the voting arrangements agreed at Nice, which give both countries disproportionate influence in the Council of Ministers.
Under the Nice Treaty, Germany, France, Britain and Italy have 29 votes in the council while Spain and Poland have 27. The draft treaty would replace the Nice system with a double majority that would allow a majority of member-states representing 60 per cent of the EU population to approve any measure in the council.
Germany, with a population of more than 80 million, says it is intolerable that Poland and Spain, with about 40 million citizens each, should have a combined voting weight of 54 compared to Germany's 29. Officials in Berlin say there is no question of Germany agreeing to any treaty in Brussels that does not include the double-majority system.
Poland and Spain have made clear that they will block any accord that diminishes their voting weight, and Poland's President Aleksander Kwasniewski said yesterday that he saw no prospect of compromise.
Italy's Prime Minister, Mr Silvio Berlusconi, maintains that he has a compromise proposal in his pocket, which he will produce at the last minute. He acknowledged yesterday, however, that it will take a miracle to find agreement in Brussels.
Among the possible compromises being discussed last night was an agreement to leave the Nice voting system in place until 2014, five years longer than the draft treaty proposes, and to raise the population threshold to 66 per cent. Furthermore, all member-states would be allowed to nominate a member of the European Commission, but the biggest six countries, including Spain and Poland, would nominate two each.
There was no sign last night, however, that either Madrid or Warsaw were willing to compromise, and some diplomats suggested that the whole question of voting in the council should be postponed for at least five years. Berlin is adamant that the issue must be resolved now, not least because it expects the new member-states to become more assertive after they join the EU.
For Germany, which is not only the EU's biggest country but has its largest share of GDP and is the biggest net contributor to the EU budget, the voting issue is central to maintaining the credibility of the EU among German citizens. For Spain and Poland, the issue goes to the heart of their sense of themselves as major players on the European stage.
The Taoiseach said last night that he could live with either the Nice voting system or the double majority and acknowledged that most of Ireland's concerns about the treaty were close to being met. The Government remains unhappy, however, with proposals to abolish the national veto on issues concerning tax fraud, fearful of opening up the prospect of more far-reaching tax harmonisation.
Mr Ahern has told his officials to be vigilant lest concessions apparently won over other issues should unravel during the complex negotiations. He has also expressed his determination to fight to the last to defend the tax veto.
The success of this weekend's talks could hinge on the performance of their idiosyncratic chairman, Mr Berlusconi, whose six months in charge of the EU have been characterised by extraordinary outbursts. A billionaire businessman who is accustomed to having his own way, he could find the strain of delicate deal-making too great a burden.
The negotiations start at 5 p.m. today, after the leaders have taken care of other EU business, including the adoption of a new security strategy and a plan to boost economic growth. After an initial statement of positions this evening, most of tomorrow is expected to be devoted to individual meetings between Mr Berlusconi and the other leaders.
The Taoiseach said last night that 10 issues remained difficult and expressed the hope that Mr Berlusconi would work quickly to reduce that number to two or three. Once the talks begin to focus on the voting issue, however, there is little anyone can do without a willingness to compromise on the part of Germany or its two adversaries.
If the summit fails, the task of finishing the treaty negotiations will fall to Ireland, which assumes the EU Presidency next month. Few believe a deal will be easier to achieve in March than it will be tomorrow, but Irish officials said this week that, after a few weeks to cool off, they will pick up the pieces of Europe's future and try again.